Question: Simplify the following expression: $p = \dfrac{1}{4n} + \dfrac{1}{10n}$
In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $4n$ and $10n$ $\lcm(4n, 10n) = 20n$ $ p = \dfrac{5}{5} \cdot \dfrac{1}{4n} + \dfrac{2}{2} \cdot \dfrac{1}{10n} $ $p = \dfrac{5}{20n} + \dfrac{2}{20n}$ $p = \dfrac{5 +2}{20n}$ $p = \dfrac{7}{20n}$